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Coconut crabs Birgus latro have recently been reclassified from Data Deficient to Vulnerable on the IUCN Red List. This is a somewhat unusual case of temporal and spatial information being used to change the IUCN status of an arthropod and it draws attention to the paucity of biological data on most invertebrate species. To be listed, two or more scientific criteria need to be documented but such data are unavailable for many invertebrates. This raises the question as to whether certain invertebrates receive more scientific attention and are hence more likely to be listed if, like the coconut crab, they are large, slow-reproducing or a dual-biome species (characteristics which make them inherently vulnerable) and whether being an indicator or a flagship species is important.

Stripes deter horseflies (tabanids) from landing on zebras and, while several mechanisms have been proposed, these hypotheses have yet to be tested satisfactorily. Here, we investigated three possible visual mechanisms that could impede successful tabanid landings (aliasing, contrast and polarization) but additionally explored pattern element size employing video footage of horseflies around differently patterned coats placed on domestic horses. We found that horseflies are averse to landing on highly but not on lightly contrasting stripes printed on horse coats. We could find no evidence for horseflies being attracted to coats that better reflected polarized light. Horseflies were somewhat less attracted to regular than to irregular check patterns, but this effect was not large enough to support the hypothesis of disrupting optic flow through aliasing. More likely it is due to attraction towards larger dark patches present in the irregular check patterns, an idea bolstered by comparing landings to the size of dark patterns present on the different coats. Our working hypothesis for the principal anti-parasite features of zebra pelage are that their stripes are sharply outlined and thin because these features specifically eliminate the occurrence of large monochrome dark patches that are highly attractive to horseflies at close distances.

Comparative studies indicate that several mammalian clades obey Gloger’s rule in that they exhibit darker coloration in humid warm climates, although the mechanisms responsible for this association still are poorly understood. We surveyed external appearances of a single species, the feral pig (Sus scrofa), shot at 48 hunting lodges across North America and matched these to potential abiotic drivers, namely: relative humidity, temperature, precipitation, and ultraviolet (UV) radiation, and to biotic factors of habitat shade and predation pressure. We found that darker animals occupy locations of greater precipitation and warmer temperatures, as expected from Gloger’s rule. The recent range expansion of S. scrofa implies selection for pelage coloration has occurred very rapidly. Separating pelage coloration into eumelanin- and phaeomelanin-based pigmentation, we found more pronounced eumelanin-based pelage in areas of higher rainfall and temperatures and UV radiation, whereas pelage phaeomelanin is related to cool dry climates with lower UV radiation. This implies that humidity or UV protection but not crypsis are the mechanisms underlying Gloger’s rule in this species and the factors driving eumelanin and phaeomelanin expression in mammalian pelage are different, reinforcing new interpretations of this venerable rule.

Primates are noted for their varied and complex pelage and bare skin coloration but the significance of this diverse coloration remains opaque. Using new updated information, novel scoring of coat and skin coloration, and controlling for shared ancestry, we reexamined and extended findings from previous studies across the whole order and the five major clades within it. Across primates, we found (i) direct and indirect evidence for pelage coloration being driven by protective coloration strategies including background matching, countershading, disruptive coloration, and aposematism, (ii) diurnal primates being more colorful, and (iii) the possibility that pelage color diversity is negatively associated with female trichromatic vision; while (iv) reaffirming avoidance of hybridization driving head coloration in males, (v) darker species living in warm, humid conditions (Gloger’s rule), and (vi) advertising to multiple mating partners favoring red genitalia in females. Nonetheless, the importance of these drivers varies greatly across clades. In strepsirrhines and cercopithecoids, countershading is important; greater color diversity may be important for conspecific signaling in more diurnal and social strepsirrhines; lack of female color vision may be associated with colorful strepsirrhines and platyrrhines; whereas cercopithecoids obey Gloger’s rule. Haplorrhines show background matching, aposematism, character displacement, and red female genitalia where several mating partners are available. Our findings emphasize several evolutionary drivers of coloration in this extraordinarily colorful order. Throughout, we used coarse but rigorous measures of coloration, and our ability to replicate findings from earlier studies opens up opportunities for classifying coloration of large numbers of species at a macroevolutionary scale.

Vast stretches of East and Southern Africa are characterized by a mosaic of deciduous woodlands and evergreen riparian forests, commonly referred to as “miombo,” hosting a high diversity of plant and animal life. However, very little is known about the communities of small-sized mammals inhabiting this heterogeneous biome. We here document the diversity and abundance of 0.5–15 kg sized mammals (“meso-mammals”) in a relatively undisturbed miombo mosaic in western Tanzania, using 42 camera traps deployed over a 3 year-period. Despite a relatively low diversity of meso-mammal species (n = 19), these comprised a mixture of savanna and forest species, with the latter by far the most abundant. Our results show that densely forested sites are more intensely utilized than deciduous woodlands, suggesting riparian forest within the miombo matrix might be of key importance to meso-mammal populations. Some species were captured significantly more often in proximity to (and sometimes feeding on) termite mounds (genus Macrotermes), as they are a crucial food resource. There was some evidence of temporal partitioning in activity patterns, suggesting hetero-specific avoidance to reduce foraging competition. We compare our findings to those of other miombo sites in south-central Africa.

Natural habitats are increasingly affected by anthropogenically driven environmental changes resulting from habitat destruction, chemical and light pollution, and climate change. Organisms inhabiting such habitats are faced with novel disturbances that can alter their modes of signaling. Coloration is one such sensory modality whose production, perception and function is being affected by human-induced disturbances. Animals that acquire pigment derivatives through diet are adversely impacted by the introduction of chemical pollutants into their environments as well as by general loss of natural habitat due to urbanization or logging leading to declines in pigment sources. Those species that do manage to produce color-based signals and displays may face disruptions to their signaling medium in the form of light pollution and turbidity. Furthermore, forest fragmentation and the resulting breaks in canopy cover can expose animals to predation due to the influx of light into previously dark environments. Global climate warming has been decreasing snow cover in arctic regions, causing birds and mammals that undergo seasonal molts to appear conspicuous against a snowless background. Ectotherms that rely on color for thermoregulation are under pressure to change their appearances. Rapid changes in habitat type through severe fire events or coral bleaching also challenge animals to match their backgrounds. Through this review, we aim to describe the wide-ranging impacts of anthropogenic environmental changes on visual ecology and suggest directions for the use of coloration both as an indicator of ecological change and as a tool for conservation.

Biologists usually pursue the adaptationist paradigm in trying to explain the functional significance of animal coloration. Here I collate instances in which coloration may be a poor match in the context of background matching, Batesian mimicry, aposematism, and colour polymorphisms. This can occur because of trade-offs with other functions, relaxed selection from predation, or colour trait neutrality. Also, mechanistic, pleiotropic and chance genetic effects can all result in a poor match to the background environment or to signaling efficiently. While biologists implicitly recognise these constraints placed on adaptive coloration, they rarely explicitly acknowledge the heterodox notion that coloration might be under weak selection or no selection at all. Unfortunately, it is difficult to show this definitively, as illustrated in an investigation into the function of colour polymorphisms in coconut crabs.

Cheetahs are thought to exhibit low genetic variability and, as a consequence, may suffer high juvenile mortality, impaired reproduction, and susceptibility to disease (O'Brien et al. 1983, 1985, 1986, 1987; Wildt et al. 1983; Marker & O'Brien 1989; Menotti-Raymond & O'Brien 1993). The species is now regularly quoted as an example of how lack of genetic diversity affects the persistence of species. Recently, however, independent criticisms have been leveled at this body of work questioning both the analysis and the standards of evidence for lack of genetic diversity (Caughley 1994; Merola 1994) as well as the evidence that cheetahs are suffering as a consequence (Laurenson et al. 1992; Caro 1994; Caro & Laurenson 1994; Caughley 1994; Laurenson 1994; Merola 1994). It is becoming clear that a loosely strung chain of poorly established findings will no longer convince a skeptical conservation community of the importance of genetics in the fate of this species. O'Brien (1994a) combines a number of points in his first rejoinder to these criticisms, including novel interpretations of ecological data that we obtained and concern about their collection and analysis. Here, we first show that this interpretation is seriously flawed and that our conclusion that predation is the key source of mortality in the wild is valid. Then, extending previous criticisms and continuing to focus on this one consequence of lack of genetic variability, we discuss O'Brien et al.'s (1985) interspecific comparison of juvenile mortality in captivity by highlighting analytical problems and presenting new data on captivity. In the Serengeti National Park, Tanzania, cheetah cubs suffered 95% mortality before reaching independence, with predation by lions and spotted hyenas accounting for the majority (73.2%) of cub deaths whose cause of death was definitely or probably known ( Laurenson 1994, Caro & Laurenson 1994). O'Brien (1994a) sug

The coconut crab Birgus latro, the largest terrestrial decapod, is under threat in most parts of its geographical range. Its life cycle involves two biomes (restricted terrestrial habitats near the coast, and salt water currents of the tropical Indian and Pacific Oceans). Its dependence on coastal habitat means it is highly vulnerable to the habitat destruction that typically accompanies human population expansion along coastlines. Additionally, it has a slow reproductive rate and can reach large adult body sizes that, together with its slow movement when on land, make it highly susceptible to overharvesting. We studied the distribution and population changes of coconut crabs at 15 island sites in coastal Tanzania on the western edge of the species' geographical range. Our aim was to provide the data required for reassessment of the extinction risk status of this species, which, despite indications of sharp declines in many places, is currently categorized on the IUCN Red List as Data Deficient. Pemba Island, Zanzibar, in Tanzania, is an important refuge for B. latro but subpopulations are fragmented and exploited by children and fishers. We discovered that larger subpopulations are found in the presence of crops and farther away from people, whereas the largest adult coconut crabs are found on more remote island reserves and where crabs are not exploited. Remoteness and protection still offer hope for this species but there are also opportunities for protection through local communities capitalizing on tourist revenue, a conservation solution that could be applied more generally across the species' range.

Aposematic coloration is traditionally considered to signal unpalatability or toxicity. In mammals, most research has focused on just one form of defense, namely, noxious anal secretions, and its black-and-white advertisement as exemplified by skunks. The original formulation of aposematism, however, encompassed a broader range of morphological, physiological, and behavioral defenses, and there are many mammal species with black-and-white contrasting patterns that do not have noxious adaptations. Here, using Bayesian phylogenetic models and data from 1726 terrestrial nonvolant mammals we find that two aspects of conspicuous coloration, black-and-white coloration patterns on the head and body, advertise defenses that are morphological (spines, large body size), behavioral (pugnacity), and physiological (anal secretions), as well as being involved with sexual signaling and environmental factors linked to crypsis. Within Carnivora, defensive anal secretions are associated with complex black-and-white head patterns and longitudinal black-and-white body striping; in primates, larger bodied species exhibit irregular patches of black-and-white pelage; and in rodents, pugnacity is linked to sharp countershading and irregular blocks of white and black pelage. We show that black-and-white coloration in mammals is multifunctional, that it serves to warn predators of several defenses other than noxious anal secretions, and that aposematism in mammals is not restricted to carnivores.

Aposematic coloration is commonly considered to signal unpalatability, yet animals advertise malodour, spines, and weaponry as well as toxins, some of which can be seen at a distance whereas others are hidden from predators. Separating defences into overt and covert categories in this way and whether they act before, during contact, or following ingestion generates new insights into the evolution of aposematism. Signals drawing attention to overt defences are difficult to fake whereas signals advertising covert defences can deceive would-be predators, and those acting later in the predatory sequence are more likely to be dishonest. These two orthogonal defence categorizations help to frame where dishonest signalling occurs in nature, set limits on deception by dishonest Batesian mimics, and prompt new questions.

Phenotypic colour polymorphisms are common in nature but their adaptive significance is often difficult to interpret. Terrestrial coconut crabs Birgus latro have cohabiting distinct red and blue co...

Conspicuous coloration in animals has many possible functions including signaling to conspecifics, or predator deterrence through confusion, intimidation, and duping; the last includes flash behavior where predators are deceived into looking for conspicuous cues exhibited in flight but that are hidden when the animal comes to rest. In an effort to see if flash behavior occurs in mammals, we made predictions about situations where conspicuous coloration (as based on human assessment) might occur in artiodactyls and lagomorphs, and other predictions as to where such coloration might be found under an intraspecific signaling hypothesis. Using phylogenetically controlled analyses, we found that across species of artiodactyls, conspicuous rumps are more likely to have evolved in larger-sized group-living species supporting an intraspecific signaling function; this was not replicated in lagomorphs. Examining those artiodactyls that can facultatively expose color patches (putative flash behavior), we discovered that this trait occurred in artiodactyls that are solitary or living in very small groups irrespective of their body size. It is therefore possible that species such as white- and black-tailed deer, which display white rumps and tails during pursuit but hide them when stationary, are using flash behavior to confuse the predator into looking for the wrong object and thereby avoid detection and suggests that this form of antipredator defense in mammals needs greater attention. We found no effects of group size or body mass on conspicuous tail or ear markings in these taxa. Many mammals have conspicuous markings on their appendages and hindquarters, the function of which is mostly unknown. We matched these markings in rabbits, hares, and pikas and in bovids and cervids to both body size and group size across species. We found that conspicuous rumps are found in group living ungulates but when we separated these into conspicuous hindquarters always on display or that could be hidden, we found that hidden markings were principally found in species living alone or in very small groups irrespective of their body size. These species may expose conspicuous patches during flight but hide them at rest fooling the predator into searching for the wrong object, a relatively newly researched defense mechanism called flash behavior.

We scored pelage coloration of pigs and peccaries and matched them to socioecological variables to assess the relative strengths of protective coloration and signaling in driving coat coloration. Using phylogenetically controlled analyses, we found that faces, bellies, and perhaps flanks are lighter in larger species; ear coloration is lighter in less-shady environments and in more-social species; white facial spots are associated with less shade and with nighttime activity; and white body spots are associated with greater sociality. There is a marginal association between striped natal coats, a classically cryptic pelage, and litter size. These findings indicate that the body coloration of Suiformes has been selected to match overall background lighting conditions in both adults and neonates, but that specific areas and color patches on the body are associated with signaling. Our study suggests that small areas of contrasting pelage coloration are superimposed on classically cryptic body plans to allow both protective coloration and signaling to operate simultaneously.

Habitat fragmentation can play a major role in the reduction of genetic diversity among wildlife populations. The Ruaha-Rungwa and Katavi-Rukwa ecosystems in south-western Tanzania comprise one of the world’s largest remaining African savannah elephant metapopulation but are increasingly threatened by loss of connectivity and poaching for ivory. To investigate the genetic structure of populations, we compared the genotypes for nine microsatellite loci in the western, central and eastern populations. We found evidence of genetic differentiation among the three populations, but the levels were low and mostly concerned the younger cohort, suggesting recent divergence probably resulting from habitat loss between the two ecosystems. We identified weak isolation by distance, suggesting higher gene flow among individuals located less than 50km apart. In a long-lived species with overlapping generations, it takes a long time to develop genetic substructure even when there are substantial obstacles to migration. Thus, in these recently fragmented populations, inbreeding (and the loss of heterozygosity) may be less of an immediate concern than the loss of adults due to illegal hunting.

Flash behavior, in which otherwise cryptic prey exhibit conspicuous coloration or noise when fleeing from potential predators, has been postulated to hinder location of prey once they become stationary. Here, using artificial computer-generated prey and humans as visual predators, we show that human subjects are more likely to abandon their search for prey that flash, compared to continuously cryptic fleeing controls. Survivorship of flashing prey was an additional 20% higher than the survivorship of continuously cryptic prey, depending on the background against which it was depicted. This survivorship advantage was consistent regardless of whether prey showed flash colors continuously or intermittently during flight. The advantage over continuously cryptic prey was highest when the flashing prey was presented first. Likewise, the more search areas containing no prey that the volunteers had initially viewed, the more likely they were to give up when there was a cryptic prey present. Collectively, these 3 findings indicate that volunteers inferred the flashing prey was absent from the search area when they failed to see a prey in the same form as they saw it move. Our results demonstrate first proof of concept: flash behavior, widely seen in taxa from insects to mammals, is an effective antipredator escape mechanism.

Lay Summary We use comparative information on carnivores and bear subspecies to investigate coloration of the giant panda. We find that white fur on the body is for matching white snowy backgrounds, black fur on legs is for camouflage in shade, but that markings on the face are for communication to other pandas or to would-be predators. The giant panda’s extrordinary pelage coloration has several different functions.

I examine Alfred Russel Wallace's six biological categories of coloration of animals and plants, and review how they have been developed over the subsequent century and a half. These categories are: protective colors; warning colors; mimicry; sexual colors; 'typical colours'; and attractive colors in flowers and fruits. Incredibly, Wallace missed little in his appraisal of the evolutionary drivers of coloration, despite being out of step with modern sexual selection theory, and his categories still characterize much of the way that this burgeoning field is organized. Even now his encyclopedic knowledge of natural history raises intriguing functional questions about coloration that still demand investigation.

Mammalian colors and color patterns are some of the most diverse and conspicuous traits found in nature and have been widely studied from genetic/developmental and evolutionary perspectives. In this review we first discuss the proximate causes underlying variation in pigment type (i.e., color) and pigment distribution (i.e., color pattern) and highlight both processes as having a distinct developmental basis. Then, using multiple examples, we discuss ultimate factors that have driven the evolution of coloration differences in mammals, which include background matching, intra- and interspecific signaling, and physiological influences. Throughout, we outline bridges between developmental and functional investigatory approaches that help broaden knowledge of mammals' memorable external appearances, and we point out areas for future interdisciplinary research.

Protected areas are the cornerstone of in situ conservation and their effective management is critical for maintaining biodiversity in the long term. In East Africa (Burundi, Kenya, Rwanda, Tanzania and Uganda) there are 1,776 protected areas (including 186 “strict” protected areas with IUCN management categories I through IV) covering more than 27% of its terrestrial area. Here we document the extent to which East African protected areas encompass ecoregions and endemic terrestrial vertebrate taxa, and using new land conversion data derived from medium to high spatial resolution satellite images, we assess how they have been encroached upon by agriculture and other land use. We find that East African protected areas cover 86% of ecoregions well (>10% threshold of ecoregion representativeness set by the Convention on Biological Diversity's Aichi Target 11), some very well (>90% - Rwenzori-Virunga montane moorlands and East African montane moorlands). In contrast, Masai xeric grasslands and shrublands, Somali Acacia-Commiphora bushlands and thickets, and Southern Swahili coastal forests and woodlands are poorly represented. Protected areas cover at least 10% of the distribution of 256 of 303 East African endemic and near-endemic terrestrial vertebrate species (the latter defined here as having 90% or more of their range in East Africa). However, 37% of these species' ranges do not have at least 10% coverage by strict PAs and only 26% of endemic species have at least half of their range covered by PAs. Encouragingly, we find that only 6.8% of East African protected areas has been converted to agriculture or other human use since gazettement. Only 1.6% of strict protected areas have been converted providing very strong evidence that strict protection is the most enduring way of safeguarding habitat. Keywords: Biodiversity, Conservation prioritization, Effectiveness, Endemic species, National parks, Representativeness

Individuals of many species are considered to rely on a single type of external appearance to escape predation but there are many notable exceptions. To develop an ecological framework to explain why some individuals employ different colour patterns as part of their defensive repertoire, we collate examples of colour change that are associated with living in different environments and microhabitats, examples of age-related colour change, colour defences tailored to different predators, and startle displays, where hidden conspicuous colour patterns are suddenly revealed. The over-arching commonality to all these examples is that the use of more than one defense-related external appearance is associated with a spatial or temporal change in predation risk. For example, coarse scale temporal changes in an animal’s background frequently select for gradual colour changes, while fine-scale spatial heterogeneity selects for more rapid colour changes and we provide a graphical framework for this. Irrespective of the mechanisms underlying colour change, using more than one colour defence appears driven by variation in predation risk rather than by idiosyncratic abilities to alter external appearances as is commonly believed, although physiological and energetic factors will play some role.

Ecological surrogacy – here defined as using a process or element (e.g., species, ecosystem, or abiotic factor) to represent another aspect of an ecological system – is a widely used concept, but many applications of the surrogate concept have been controversial. We argue that some of this controversy reflects differences among users with different goals, a distinction that can be crystalized by recognizing two basic types of surrogate. First, many ecologists and natural resource managers measure “indicator surrogates” to provide information about ecological systems. Second, and often overlooked, are “management surrogates” (e.g., umbrella species) that are primarily used to facilitate achieving management goals, especially broad goals such as “maintain biodiversity” or “increase ecosystem resilience.” We propose that distinguishing these two overarching roles for surrogacy may facilitate better communication about project goals. This is critical when evaluating the usefulness of different surrogates, especially where a potential surrogate might be useful in one role but not another. Our classification for ecological surrogacy applies to species, ecosystems, ecological processes, abiotic factors, and genetics, and thus can provide coherence across a broad range of uses.

Tanzania, arguably mainland Africa's most important nation for conservation, is losing habitat and natural resources rapidly. Moving away from a charcoal energy base and developing sustainable finance mechanisms for natural forests are critical to slowing persistent deforestation. Addressing governance and capacity deficits, including law enforcement, technical skills, and funding, across parts of the wildlife sector are key to effective wildlife protection. These changes could occur in tandem with bringing new models of natural resource management into play that include capacity building, corporate payment for ecosystem services, empowering nongovernmental organizations in law enforcement, greater private-sector involvement, and novel community conservation strategies. The future of Tanzania's wildlife looks uncertain-as epitomized by the current elephant crisis-unless the country confronts issues of governance, embraces innovation, and fosters greater collaboration with the international community.

While handling large kills, mesocarnivores are particularly vulnerable to kleptoparasitism and predation from larger predators. We used 35 years of observational data on cheetah (Acinonyx jubatus) hunts in Serengeti National Park to investigate whether cheetahs’ prey handling behavior varied in response to threats from lions (Panthera leo) and spotted hyenas (Crocuta crocuta). Male cheetahs and single females, whose main threat was kleptoparasitism, minimized time on the kill by being less vigilant and eating quickly, thereby shortening their handling times. Mothers with cubs showed a different strategy that prioritized vigilance over speed of eating, which increased time spent handling prey. Vigilance allowed them to minimize the risk of their cubs being killed while giving cubs the time they need to eat at the carcass. Flexible behavioral strategies that minimize individual risk while handling prey likely allow mesocarnivores to coexist with numerous and widespread apex predators. Medium-sized carnivores like cheetahs face the challenge of coexisting with larger carnivores that steal their kills and kill their cubs. We investigated how cheetahs modify their behavior on kills to minimize risks from larger predators. Using 35 years of data on 400+ cheetah hunts across 159 individuals, we found that cheetahs without cubs whose primary danger is having their kill stolen spent little time engaged in vigilance and instead ate quickly, reducing the risk of theft. Mothers with cubs, however, took a slower approach and were more vigilant while handling prey to avoid cub predation by lions and spotted hyenas. The ability of cheetahs to modify their prey handling behavior depending on the type of risk they face likely allows them to coexist with numerous larger carnivores.

Fewer than 40,000 lions are left in Africa, perhaps 40% of which reside in Tanzania. Lions in East Africa are commonly killed in situations where they prey on livestock, either to retaliate for loss or avert future attacks. Among the Sukuma, Tanzania’s largest cattle-raising ethnic group, tradition allows a lion killer to visit households, perform a special dance, and demand rewards for ridding the area of a potentially dangerous predator. Here we document how this tradition of gift-giving provides sufficient economic incentive that lion killing continues to persist in the face of a near absence of livestock loss from lions. Contemporary lion killers no longer act as avengers, retaliating for loss or averting future attacks, but as hunters, pursuing non-threatening lions far from residential and grazing areas and often inside protected areas. Our study reveals that Sukuma householders are less likely to reward a lion dancer if they have received frequent visits from dancers (indicative of donor fatigue) and if they perceive change in motivation from avenging to hunting. These findings suggest that it may be possible to reduce illegal killing of lions by working through Sukuma institutions responsible for collective action within the local community, and to remove the economic incentive for killing non-problem lions.

Top predators can dramatically suppress populations of smaller predators, with cascading effects throughout communities, and this pressure is often unquestioningly accepted as a constraint on mesopredator populations. In this study, we reassess whether African lions suppress populations of cheetahs and African wild dogs and examine possible mechanisms for coexistence between these species. Using long-term records from Serengeti National Park, we tested 30 years of population data for evidence of mesopredator suppression, and we examined six years of concurrent radio-telemetry data for evidence of large-scale spatial displacement. The Serengeti lion population nearly tripled between 1966 and 1998; during this time, wild dogs declined but cheetah numbers remained largely unchanged. Prior to their local extinction, wild dogs primarily occupied low lion density areas and apparently abandoned the long-term study area as the lion population 'saturated' the region. In contrast, cheetahs mostly utilized areas of high lion density, and the stability of the cheetah population indicates that neither high levels of lion-inflicted mortality nor behavioural avoidance inflict sufficient demographic consequences to translate into population-level effects. Population data from fenced reserves in southern Africa revealed a similar contrast between wild dogs and cheetahs in their ability to coexist with lions. These findings demonstrate differential responses of subordinate species within the same guild and challenge a widespread perception that lions undermine cheetah conservation efforts. Paired with several recent studies that document fine-scale lion-avoidance by cheetahs, this study further highlights fine-scale spatial avoidance as a possible mechanism for mitigating mesopredator suppression.

Mammals have evolved several morphological and behavioral adaptations to reduce the risk of predation, but we know little about the ecological factors that favor their evolution. For example, some mammalian carnivores have the ability to spray noxious anal secretions in defense, whereas other species lack such weaponry but may instead rely on collective vigilance characteristic of cohesive social groups. Using extensive natural history data on 181 species in the order Carnivora, we created a new estimate of potential predation risk from mammals and birds of prey and used comparative phylogenetic methods to assess how different sources of predation risk and other ecological variables influence the evolution of either noxious weaponry or sociality in this taxon. We demonstrate that the evolution of enhanced spraying ability is favored by increased predation risk from other mammals and by nocturnality, but the evolution of sociality is favored by increased predation risk from birds of prey and by diurnality, which may allow for enhanced early visual detection. These results suggest that noxious defenses and sociality are alternative antipredator strategies targeting different predator guilds under different lighting conditions.

Carcasses of 11 medium-sized species of mammals along two-lane highways in northern Central Valley, California, were counted between 1997 and 2007 to obtain an indirect measure of changes in mammalian populations over time. Over this period, 1.23 mammalian carcasses were recorded per 100 km, lower than that reported in several other parts of North America. Each species was classified as human-sensitive, suburban-adaptable, or human-adapted according to the use of the land in which it was principally located. In contrast to simple predictions that populations of more human-sensitive species would be in decline and human-associated species would be increasing, indices of populations of all species showed little change once volume of traffic had been taken into account. Therefore, populations of most of the common mammals in the study area appear relatively stable at present. Annual fluctuations in populations of one species did not mirror those of other species of mammals suggesting that each speci...

Aposematism and crypticity are viewed as mutually exclusive antipredator defense strategies with skunks being a classic example of the former. Skunks can spray noxious anal secretions and many species (Conepatus and Mephitis spp.) have bold blocks of white fur on black pelage, but spotted skunks (Spilogale sp.) have white spots and lines on a black coat suggesting an additional function. We tested the possibility that spotted skunks are conspicuous at close range but cryptic at a distance. Using quantitative measures of colouration extracted from photographs of taxidermied western spotted skunk, bobcat and striped skunk mounts taken at ≤ 5 m, we found that spotted skunk colouration was significantly more conspicuous than the cryptic bobcat but not than the striped skunk. Differences between mount and background colouration were significantly greater for spotted skunks than for bobcats but not for striped skunks. Both sets of results indicate that spotted skunks match their background poorly when viewed cl...

We summarize 18 common misgivings that animal behaviourists raise about becoming involved in conservation. We argue that many of the supposed institutional and interdisciplinary differences break down under scrutiny; that the supposed basic-applied dichotomy is often imaginary or insufficient to prevent interchange of ideas between behaviour and conservation; and that arguments about professional lifestyle, scientific inflexibility and despair are not adequate justifications for remaining on the sidelines. We suggest that many studies of animal behaviour are relevant to solving conservation problems, and we therefore encourage behaviourists to contribute more strongly to finding practical solutions to the contemporary conservation crisis.

Prey preferences of top carnivores in African ecosystems are well known, but far less is understood about the preferences of human hunters and the effects of their hunting activities. We interviewed 82 hunters living in Mpimbwe Division adjacent to Katavi National Park and Rukwa Game Reserve in western Tanzania. We compared stated preferences for different species of mammals with that reportedly hunted, and we used reportedly hunted species in Jacob's indices to examine proportional offtake of each species that would be expected as based on both encounters and density estimates of the wildlife species. Then, using general linear models, we tested whether the derived indices of preference were affected by the proportional density, habitat preference, and body mass of the mammalian prey species. We found that hunters would like to kill large mammals but, instead, hunt opportunistically when they cannot realize these preferences and so end up taking smaller species than would be expected. We found that a surprising amount of rarer species is taken in this ecosystem. Our study helps to unveil novel information that wildlife managers can use to predict what hunters take most from protected areas, and it highlights the importance of treating humans as apex predators in modern day Africa.

Pinnipeds vary in adult pelage color and pattern ranging from uniform white to black or brown and from solid coloration to subtle spotted or bold markings. Moreover, pelage color often differs by sex and age with neonates having radically different color and patterning from those of adults. We explored the functional significance of these patterns in 34 species of pinniped using comparative phylogenetic analyses. We found strong evidence to support the hypothesis of background matching on land because species in which adults or pups have white pelage live in Arctic regions and are subject to terrestrial predation. We also found evidence supporting the hypothesis of background matching at sea because spotted species forage in well-lit shallow waters on-shelf and dark pinnipeds forage in deep dark waters off-shelf. Neonates are black for species lacking terrestrial predators on islands or in caves where selection on crypsis is relaxed. Distinctive markings may be used for intraspecific communication. Sexually dichromatic pinnipeds are highly polygynous and copulate on land, suggesting a role for male coloration in contests for access to females. Functional differences in the coloration of pinnipeds and cetaceans reveal differences in underlying selection pressures, in particular those derived from pinnipeds' amphibious lifestyle.

Several large mammals such as the black and white giant panda Ailuropoda melanoleuca, the mottled giraffe Giraffa camelopardalis, and striped and russet okapi Okapia johnstoni have striking and wel...

IT HAS BECOME COMMONPLACE to remark that humans are now the dominant environmental force on the Earth. The indications are strong and diverse. They range from paleontologists reaching a consensus that humans contributed to megafaunal extinctions on at least two continents, North America and Australia;1 recognition that formerly intact marine ecosystems have changed enormously;2 suggestions that climate has changed sufficiently that no ecosystem is immune from alterations in species composition;3 remarks that pollution is widespread even in Antarctica;4 and arguments that human predation on mammals is pernicious and the principal driver of changes in phenotypic traits of exploited species in many areas.5 Some scientists use geographic data to show that human activities affect almost every terrestrial system (e.g., the human footprint6). Indeed, the current epoch is now being referred to as “the Anthropocene,”7 which has led geologists to formally debate stratigraphic evidence for this new phenomenon and to argue over not if but when it began.8 With the catchword Anthropocene in ascendancy, one might easily come away with the impression that nowhere on Earth is natural, in one of the word’s specific meanings of ecosystems being untouched by humans,9 and indeed it is common to hear the phrase “humans have altered everything.”

Several species of terrestrial carnivores (Mammalia: Carnivora) have bold contrasting color patterns that, in some species, apparently signal possession of noxious anal gland secretions, or even physical strength and great ferocity; yet the evolutionary drivers of both placement and patterning of these contrasting pelage colors on the body, and the ecological selection pressures underlying them, have yet to be systematically examined. Here we explore these issues and find not only that both boldly colored and dichromatic species do indeed often use anal gland secretions for defense, but also that such species are stockier, and live in more exposed habitats where other forms of antipredator defense are limited. We also show that white dorsa are found in sprayers that are primarily nocturnal; that horizontal stripes are found in species that have an ability to spray anal secretions accurately; and that facial stripes are found in burrowing species that typically leave only their heads exposed to attack. Our phylogenetic reconstructions suggest that aposematic coloration has evolved more than once in terrestrial carnivores. We finish by outlining five evolutionary routes for patterns of pelage coloration in this taxon.

Although long-term monitoring is viewed as an essential part of conserving wildlife populations, it is currently carried out in surprisingly few protected areas in Africa. Here, data from a 16-year vehicle transect monitoring programme in Katavi National Park, western Tanzania, are presented. These data provide information on large mammal densities, identify declines in populations of several large mammal species as based on encounter rates, support worrying trends observed in aerial census data and shed light on the effectiveness of recent changes in legal protection. Ground and aerial surveys confirmed that waterbuck, topi, warthog, lion and spotted hyaena populations are all in decline and that this should be a cause for concern. Counting animals by driving vehicle transects is relatively easy and inexpensive to carry out, and data here show that such counts have several pay-offs for conservation managers especially in identifying population declines; counts should be employed more often in East Africa and elsewhere.

Cetaceans show many of the classic mammalian colouration patterns, such as uniform colouration, countershading, and prominent patches of colour, all within one relatively small taxon. We collated all the functional hypotheses for cetacean colouration that have been put forward in the literature and systematically tested them using comparative phylogenetic analyses. We found that countershading is a mechanism by which smaller cetacean species may avoid being seen by their prey. We discovered that prominent markings are associated with group living, fast swimming, and ostentatious behaviour at the surface, suggesting that they function in intraspecific communication. White markings on several parts of the body seem to be involved in the capture of fish, squid, and krill. Therefore, several different selection pressures have shaped the great diversity of skin colouration seen in extant cetaceans, although background matching, disruptive colouration and interspecific communication do not appear to be involved.

Reptiles of Katavi National Park, western Tanzania, are from different biomes Tim Caro*, Owen ‘Squack’ Evans, Emily Fitzherbert, Toby A. Gardner, Kim Howell, Robert Drewes and H. Bradley Shaffer Center for Population Biology and Department of Wildlife, Fish and Conservation Biology, University of California, Davis, CA 95616, U.S.A., Tanzania Wildlife Research Institute, PO Box 661, Arusha, Tanzania, PO Box 345, Usa River, Tanzania, Conservation Science Group, Department of Zoology, University of Cambridge, Downing Street, Cambridge CB2 3EJ, U.K., Department of Zoology and Wildlife Conservation, University of Dar es Salaam, Tanzania, PO Box 35064, Dar es Salaam, Tanzania, California Academy of Sciences, 55 Music Concourse Drive, Golden Gate Park, San Francisco, CA 94118, U.S.A. and Center for Population Biology and Department of Evolution and Ecology, University of California, Davis, CA 95616, U.S.A.

Turtle carapaces clearly function as antipredator adaptations, but their varied structure has rarely been matched to differential predation pressure in nature. In addition, the role of antipredator behaviors, and how they interact with morphological defenses in turtles, is poorly understood. Here we show that a small turtle, Pelusios subniger, is found predominately in pools and watercourses where the Nile crocodile, Crocodylus niloticus, a species that imposes intense predation pressure on them, is absent. Our ecological data are consistent with the interpretation that P. subniger can share the same ecological landscape with C. niloticus through behavioral avoidance.

Tanzania holds most of the remaining large populations of African lions (Panthera leo) and has extensive areas of leopard habitat (Panthera pardus), and both species are subjected to sizable harvests by sport hunters. As a first step toward establishing sustainable management strategies, we analyzed harvest trends for lions and leopards across Tanzania's 300,000 km(2) of hunting blocks. We summarize lion population trends in protected areas where lion abundance has been directly measured and data on the frequency of lion attacks on humans in high-conflict agricultural areas. We place these findings in context of the rapidly growing human population in rural Tanzania and the concomitant effects of habitat loss, human-wildlife conflict, and cultural practices. Lion harvests declined by 50% across Tanzania between 1996 and 2008, and hunting areas with the highest initial harvests suffered the steepest declines. Although each part of the country is subject to some form of anthropogenic impact from local people, the intensity of trophy hunting was the only significant factor in a statistical analysis of lion harvest trends. Although leopard harvests were more stable, regions outside the Selous Game Reserve with the highest initial leopard harvests again showed the steepest declines. Our quantitative analyses suggest that annual hunting quotas be limited to 0.5 lions and 1.0 leopard/1000 km(2) of hunting area, except hunting blocks in the Selous Game Reserve, where harvests should be limited to 1.0 lion and 3.0 leopards/1000 km(2) .